Picture this: in the sequel, We see that Chelsea is actually a real character and she’s not like her mother. It would have her side of the story about what she was actually doing before she meet Ruby, and she wanted to change the world too, but got mixed up by some lie she must’ve got, which would explain why she didn’t came to the house party. she explains why she turned bad, and doesn’t want to follow her mother’s fintails anymore. Perfect example is she has sisters who were forcing her into a life she doesn’t want. Like trying to conquer the ocean, having her mother’s terrible goal, and to not make any friends at all! Once she steps onto land, she sees Ruby Gillman and sees that she’s just like her because she too was forced to a life she hates. As the 2 of them become besties, perhaps Chelsea was taken back into the ocean instead of willingly be brave to meet Agatha, because Chelsea’s sisters were manipulating her into believing that Agatha killed nerrisa, and that made her so angry that she believed the krakens were the actual monsters. So she took the trident, betrayed Ruby, and pretended to be her mother because her sisters convinced her to take her name, and legacy. After she got defeated she noticed that Ruby stopped her grandmother from killing her, and made her wonder what the truth really was. When she learns the truth, she tries to earn the trust of the entire Gillman family by being her real good and nice self, as she and the family saves Ruby as she gets kidnapped from a new threat under the ocean. Chelsea then tries to convince her sisters that mermaids need to change their hearts, so she can be best friends with ruby again. And finally the two of them get to plan their future together as rulers of the sea with krakens and mermaids living together in harmony! The End!